From df5a19f4688f5146d662014ce8354b14f71cef85 Mon Sep 17 00:00:00 2001
From: Shobhit Chittora <chittorashobhit@gmail.com>
Date: Mon, 20 Aug 2018 21:32:31 +0530
Subject: [PATCH] child_process: handle undefined/null for fork() args

PR-URL: https://github.com/nodejs/node/pull/22416
Fixes: https://github.com/nodejs/node/issues/20749
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Matheus Marchini <mat@mmarchini.me>
---
 lib/child_process.js                          |  5 +++
 test/fixtures/child-process-echo-options.js   |  1 +
 .../test-child-process-fork-options.js        | 37 +++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 test/fixtures/child-process-echo-options.js
 create mode 100644 test/parallel/test-child-process-fork-options.js

diff --git a/lib/child_process.js b/lib/child_process.js
index bc86ab3797ad17..f08acd76c7953b 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -69,6 +69,11 @@ exports.fork = function fork(modulePath /* , args, options */) {
     args = arguments[pos++];
   }
 
+  if (pos < arguments.length &&
+      (arguments[pos] === undefined || arguments[pos] === null)) {
+    pos++;
+  }
+
   if (pos < arguments.length && arguments[pos] != null) {
     if (typeof arguments[pos] !== 'object') {
       throw new ERR_INVALID_ARG_VALUE(`arguments[${pos}]`, arguments[pos]);
diff --git a/test/fixtures/child-process-echo-options.js b/test/fixtures/child-process-echo-options.js
new file mode 100644
index 00000000000000..04f3f8dcffe6a9
--- /dev/null
+++ b/test/fixtures/child-process-echo-options.js
@@ -0,0 +1 @@
+process.send({ env: process.env });
diff --git a/test/parallel/test-child-process-fork-options.js b/test/parallel/test-child-process-fork-options.js
new file mode 100644
index 00000000000000..5efb9bdbb49735
--- /dev/null
+++ b/test/parallel/test-child-process-fork-options.js
@@ -0,0 +1,37 @@
+'use strict';
+const common = require('../common');
+const fixtures = require('../common/fixtures');
+
+// This test ensures that fork should parse options
+// correctly if args is undefined or null
+
+const assert = require('assert');
+const { fork } = require('child_process');
+
+const expectedEnv = { foo: 'bar' };
+
+{
+  const cp = fork(fixtures.path('child-process-echo-options.js'), undefined,
+                  { env: Object.assign({}, process.env, expectedEnv) });
+
+  cp.on('message', common.mustCall(({ env }) => {
+    assert.strictEqual(env.foo, expectedEnv.foo);
+  }));
+
+  cp.on('exit', common.mustCall((code) => {
+    assert.strictEqual(code, 0);
+  }));
+}
+
+{
+  const cp = fork(fixtures.path('child-process-echo-options.js'), null,
+                  { env: Object.assign({}, process.env, expectedEnv) });
+
+  cp.on('message', common.mustCall(({ env }) => {
+    assert.strictEqual(env.foo, expectedEnv.foo);
+  }));
+
+  cp.on('exit', common.mustCall((code) => {
+    assert.strictEqual(code, 0);
+  }));
+}